Modular air conditioner for a bus

ABSTRACT

A module is provided for attachment to the roof of a bus and includes all of the necessary components for conditioning the return air from the passenger compartment and delivering conditioned air thereto. A plurality of modules can be mounted in various relationships to collectively provide the total capacity required by the bus. Each module includes an evaporator section, a condenser section and a power section including a compressor and an inverter. The evaporator sections have a return air compartment that extends a substantial distance across the roof of the bus such that a single design can meet the needs of various return air duct installations of various types of buses. Provision is made for the selective mixing of return air with fresh air, with the mixture then being passed by the evaporator blower through the evaporator coils and into the supply air ducts. The frames of the modules are attached to the roof of the bus by rails which are properly spaced to accommodate the module frames and allow their selective longitudinal placement.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to the following pending applications beingconcurrently filed herewith and assigned to the assignee of the presentinvention:

Title Ser. No.: Modular Rooftop Air Conditioner for a Bus 10/429,584Modular Bus Air Conditioning System 10/429,481 Supply Air Blower Designin Bus Air Conditioning Units 10/429,456 Bus Rooftop Condenser Fan10/429,453 Method and Apparatus for Refreshing Air in a Bustop Air10/429,455 Conditioner Coil Housing Design for a Bus Air ConditioningUnit 10/429,454 Integrated Air Conditioning Module for a Bus 10/430,092Fresh Air Intake Filter and Multi Function Grill 10/429,451 IntegratedAir Conditioning Module for a Bus 10/429,583 Modular Air Conditioner fora Bus 10/429,424 Modular Air Conditioner for a Bus Rooftop 10/429,437Evaporator Section for a Modular Bus Air Conditioner 10/429,423 WideEvaporator Section for a Modular Bus Air 10/429,484 ConditionerCondensate Pump for Rooftop Air Conditioning Unit 10/429,391 CondensateRemoval System Rooftop Air Conditioning 10/429,452 Modular Rooftop UnitSupply Air Ducting Arrangement 10/429,390 Configuration for Modular BusRooftop Air Conditioning 10/429,389 System Unibody Modular Bus AirConditioner 10/429,388

BACKGROUND OF THE INVENTION

This invention relates generally to air conditioning systems and, moreparticularly, to an air conditioning system for the rooftop of a bus.

The most common approach for air conditioning a bus is to locate the airconditioning components on the rooftop thereof Inasmuch as power isavailable from the engine that drives the bus, it has become commonpractice to locate the air conditioning compressor near the drive enginesuch that the drive engine is drivingly connected to the compressor,with the compressor then being fluidly interconnected to the airconditioning system on a rooftop of a bus. This, of course, requiresrather extensive piping between the engine compartment and the airconditioning unit, thereby increasing installation and maintenancecosts.

Another problem with such existing systems is that the speed that thecompressor is driven is dependent on the speed in which the drive engineis running. Thus, when the drive engine is idling in a parking lot, forexample, the compressor is running at a relatively slow speed which maynot be sufficient to provide the desired degree of air conditioning. Itis therefore generally necessary to oversize the compressor in order toobtain the performance needed under these conditions.

Others problems associated with such a motor driven compressor system isthat the open drive compressor needs a shaft seal and a mechanicalclutch, both of which are subject to maintenance problems. Further,since DC power is available on a bus, DC motors have been used for theair conditioning system. In general, DC motors are not as reliable as ACmotors since they have brushes that wear out, and brushless motors arerelatively expensive.

In addition to the problems discussed hereinabove, it is recognized,that because the wide variety of bus types and application requirements,it has been necessary to provide many different types and variations ofair conditioning systems in order to meet these different requirementsand vehicle interfaces. As a result, the manufacturing and installationcosts, and sustaining engineering resources that are necessary in orderto properly maintain and service these units, are relatively high.

It is therefore an object of the present invention to provide animproved bus top air conditioning system.

Another object of the present invention is the provision for a bus airconditioning system which is effective at all operating engine speeds ofthe bus, while at the same time does not require an oversizedcompressor.

Yet another object of the present invention is the provision forreducing the manufacturing, installation, and maintenance costs of a busair conditioning system.

Yet another object of the present invention is the provision for a busrooftop air conditioning system which is economical to manufacture andeffective in use.

These objects and other features and advantages become more readilyapparent upon reference to the following descriptions when taken inconjunction with the appended drawings.

SUMMARY OF THE INVENTION

Briefly, in accordance with one aspect of the invention, an airconditioning module is assembled with its condenser coil, evaporatorcoil and respective blowers located within the module and so situatedthat a standard module can accommodate various installation interfaceswith different types and locations of return air and supply air ducts ona bus.

In accordance with another aspect of the invention, each of a pluralityof modules are installed in a centered relationship with respect to alongitudinal centerline of the bus and extend transversely across thewidth of the bus. The number and length of modules is dependent on thetotal air conditioning capacity requirement of the bus.

By yet another aspect of the invention, each of the identical modulesinclude all the necessary components with electrical power beingprovided to the electrical components by an inverter/controller that ispowered by an engine motor driven generator.

By another aspect of the invention provision is made for mounting theframes of multiple modules in adjacent or longitudinally spacedpositions on the bus rooftop by way of a pair of longitudinallyextending rails.

By still another aspect of the invention the evaporator section of themodules has a return air compartment that spans a substantial width ofthe bus to thereby accommodate various sizes and types of return airinterface requirements.

By yet another aspect of the invention the evaporator section of eachmodule has three different vertical levels to accommodate the respectiveincoming flows of return air and replenishing fresh air, and includes amixer for selectively varying the amount of each which passes to the fanand then to the evaporator coil.

In the drawings as hereinafter described, a preferred embodiment isdepicted; however various other modifications and alternateconstructions can be made thereto without departing from the true spiritand scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a module as installed on the rooftop ofa bus in accordance with a preferred embodiment of the invention.

FIG. 2 is a perspective view of a module with the top cover removed.

FIG. 3 is a schematic illustration of the electrical and refrigerantcircuits within the module in accordance with the preferred embodimentof the invention.

FIG. 4 is a front elevational view of the condenser section of themodule.

FIG. 5 is a front elevational view of the evaporator section of themodule.

FIGS. 6-8 are front elevational views of the evaporator section asapplied to different types of bus rooftops.

FIG. 9 is a perspective view of the evaporator section with its fan andmixer.

FIG. 10 is a bottom perspective view thereof.

FIG. 11 is a perspective view of the evaporator section showing thefresh air flap in the fully opened position.

FIG. 12 is a perspective view thereof with the flap in an intermediateposition.

FIG. 13 is a perspective view thereof with the fresh air flap in theclosed position.

FIG. 14 is a perspective view of a pair of modules in adjacentrelationship.

FIG. 15 is a perspective view of three modules in adjacent relationship.

FIG. 16 is a perspective view of four modules in adjacent relationship.

FIG. 17 is a perspective view of the modules frames and related mountingrails.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The inventive module is shown generally at 10 in FIG. 1 as applied tothe rooftop 11 of a bus in accordance with the present invention.Electrical power is provided to the module 10 by way of line 12, whichin turn receives its power from a generator 13 driven by the bus engine14 as shown.

The module 10 interfaces with openings in the bus top so that fanswithin the module 10 cause the return air from the passenger compartmentto flow upward into the module 10 where it is conditioned, and theconditioned air to then flow downwardly into supply air ducts that carrythe conditioned air to the passenger compartment. The various structuresand the manner in which they interface with the bus rooftop 11 will morefully described hereinafter.

In FIG. 2, the module 10 is shown with its cover removed to include aframe 16 with an evaporator section 17 attached to one end thereof and acondenser section 18 attached to the other end thereof. Adjacent thecondenser section 18 is a power section 19 which includes a compressor21 and an inverter/controller 22. The manner in which they providedmotive power to the refrigerant circuit and electrical power to theelectrical components of the module 10 will be more fully describedhereinafter.

The evaporator section 17 comprises a pair of identical units inabutting end-to-end relationship with each unit including an evaporatorblower 23 with its evaporator blower motor 24, and an evaporator coil26. Briefly, the evaporator blower 23 draws in return air from thepassenger compartment of the bus, and fresh air from outside and passesa mixture of the two through the evaporator coil 26 to be conditioned,after which it flows back to the passenger compartment by way of thesupply air ducts. This will be more fully described hereinafter.

Within the condenser section 18, there is provided a condenser fan 27driven by an electric motor, and a pair of condenser coils 28 and 29.Briefly, the condenser fan draws air upwardly to create a vacuum below,which in turn causes fresh air to be drawn through the condenser coils28 and 29 to condense the refrigerant flowing through the coils 28 and29. The resulting warm air is then discharged upwardly to the atmosphereby the fan 27.

Referring now to FIG. 3, the module 10 is shown with its electricalconnection by way of line 12 to the generator 13 and driving motor 14.The inverter/controller 22 receives AC power from the generator, oralternator, and, in turn provides discretely controlled AC power to theevaporator blower motor 24, the drive motor 31 of the condenser fan 27and the drive motor 32 of the compressor 21. A plurality of controlsensors, shown generally at 33 provide feedback to theinverter/controller 22 as necessary for it to control the AC power beingdelivered to the various drive motors.

As will be seen, the refrigeration circuit is a closed circuit throughwhich the refrigerant flows from the compressor 21 to the condenser 29,an expansion valve 34, the evaporator 26 and finally back to thecompressor 21. This is accomplished in a conventional manner.

It will be seen that the module 10 is self-contained with all of thenecessary components, with the only input thereto being the electricalpower by way of the electrical line 12. Other modules, indicated asnumber 2-6 are identically configured and are powered and controlled inthe same manner.

Returning now to the condenser section 18 as shown in FIG. 4, the flowof air as caused by the condenser fan 27 is shown by the arrows. Freshair is drawn in through the fresh air intake openings 36 and 37, passesthrough the respective condenser coils 28 and 29 and then flows upwardlythrough the condenser fan 27 and the condenser outlet air opening 38 asshown.

Within the evaporator section 17 as shown in FIG. 5, the relatively warmreturn air flows upwardly from a return air duct communicating with thepassenger compartment and enters a return air compartment 39 of theevaporator section 17 as shown by the arrows. The evaporator blower 23causes the return air to flow upwardly to its inlet at the top, and atthe same time, fresh air may be brought in by way of a fresh air flap ina manner to be described hereinafter. A mixture of the two airflowstreams is thus admitted at the intake of the evaporator blower 23 andcaused to flow downwardly and outwardly as indicated by the arrows tothe evaporator coils 26. After passing through the evaporator coil 26 itis then caused by a curved cowling 41 to flow downwardly to a supply airduct leading to the passenger compartment. Thus, while the module isoperating, there is a constant circuitous flow of return air out of thepassenger compartment and of conditioned air back into the passengercompartment. The amount of return air that is discharged to the outside,and also the amount of fresh air that is brought into the circuit fromthe outside is controlled by the selective movement of the fresh airflaps as will be described hereinafter. There are shown in FIGS. 6-8installations of the module 10 with various types of buses andassociated return air and supply air ducts. In FIG. 6, for example, awide bus installation is shown wherein the existing duct work within thebus includes supply air ducts 43 and 44 near the lateral sides of thebus, and return air ducts 46 and 47 that are closer to the center lineof the bus, but are substantially spaced apart. Here it will be seenthat the return air ducts 46 and 47 communicate directly with the returnair compartment 39 of the module 10, but at a position at near the outerend thereof.

In FIG. 7, which shows a narrow bus installation, again the supply airducts 48 and 49 are near the transverse sides of the bus. But the returnair ducts 51 and 52 are abutting each other at the center line of thebus. Again, the return air ducts 51 and 52 fluidly communicate with thereturn air compartment 39, but at the other end thereof.

Finally, in FIG. 8 there is shown a curved top bus wherein the supplyair ducts 53 and 54 are again near the transverse sides of the bus, butthe return air ducts 56 and 57 are in intermediate positions, relativelyclose to the center line but substantially spaced apart. Again, thereturn air ducts 56 and 57 fluidly communicate with the return aircompartment 39, but at a position intermediate the two ends thereof.

It will thus be seen that the same identical module is so constructedand designed that it can accommodate any of these various installationrequirements without modification of the module itself. That is, theconditioned air discharge opening 40 is sufficiently large and thetransverse direction to accommodate the various supply air ductorientations, and, more importantly, the return air compartment 39 isrelatively large in the transverse direction so as to accommodate eachof the various types of return air duct configuration as shown.

In order to describe the evaporator section 17, and the manner in whichthe flow of return air is mixed with the flow of fresh air, reference ismade to FIGS. 9-13. In FIG. 9, the evaporator blower 23 is shown withits blower inlet 58 receiving the air to be cooled, which flowsdownwardly and then outwardly toward and through the evaporator coil 26as shown by the arrows. The cold air then flows further outwardly anddownwardly to the supply air duct as shown by the arrow at the left. Theair passing into the blower inlet 58 is a mixture of return air thatflows upwardly through the channel 59 and the fresh air that flows inthrough the fresh intake window 41 as shown by the arrows. That is,referring to FIG. 10, the return air which has come into the return aircompartment 39 below the evaporator blower 23 flows into an opening 61and upwardly through the channel 59 as shown by the arrows. When thereturn air flow reaches the top of the channel 59 the amount of returnair, and also the amount of fresh air passing through the fresh airintake window 41 will depend on the position of the fresh air flap 42.

In FIG. 11, the fresh air flap 42 is shown as attached to a rod 62,which in turn is attached to a rotatable lever 63 for selectivelyrotating the fresh air flap on its axis to thereby vary the size of theopening at the fresh air intake window 41. The position of the fresh airflap 42 is the fully opened position wherein there is no restriction ofthe flow of fresh air that is coming into the fresh air intake window41. When in this position, the fresh air flap also closes off the exitside of the flow channel 59 in which the return air is flowing upwardly.Thus, when the fresh air flap 42 is in the fully opened position, noneof the return air passes upwardly into the evaporator blower 23 and theonly, and the only air passing into the evaporator blower 23 and on tothe evaporator coil 26 is the fresh air coming in through the fresh airintake window 41. The return air in the channel 59 is thus caused toflow out into the atmosphere by way of an opening to be describedhereinafter.

In FIG. 12, the lever 63 and attached rod 62 are selectively moved toadjust the fresh air flow 32 to an intermediate position wherein theexit opening at the top of the channel 59 is uncovered, while at thesame time the fresh air flap 42 tends to offer some restriction to theflow of fresh air coming into the fresh air intake window 41. The airbeing taken into the blower inlet 58 is thus a mixture of return air andfresh air, with only a portion of the return air being discharged to theoutside.

FIG. 13 shows the fresh air flap in the closed position wherein itcompletely blocks off the fresh air intake window 41 and completelyuncovers the channel 59. Thus, when in this position, all of the returnair, and no fresh air, passes into the blower inlet 58, through theevaporator coil 26 and to the supply air ducts of the bus. It should, ofcourse, be understood that the fresh air flap 42 maybe placed in anyintermediate position not shown in order to obtain the desired mix asappropriate to meet the cooling needs as determined by the load in thepassenger compartment of the bus, as well as the environmentalconditions outside.

Of a structure of the evaporator section 17 as described hereinabovewill be recognized as providing three levels within the evaporatorsection in which the flow of air occurs. At a lower level, the returnair compartment 39 provides for a flow of return air from the return airduct to the evaporator section 17. At an intermediate level, there is achannel to guide the flow of return air upwardly, and in a parallelroute, to provide the flow of mixed air downwardly through theevaporator blower 23. At a third, upper, level, there is a spaceprovided for the flow of fresh air through the fresh air intake window41, for the mixture of that fresh air with the return air blowingupwardly, and for the mixture to flow into the intake 58 of the blower58.

While a single unit is shown in its installed position on the bus inFIG. 1, the present module is designed to be “ganged” with one or moreother modules to provide a collective air conditioning capacity asnecessary to meet the needs of the bus. In FIG. 14, a pair of modulesare stacked together, with one being turned, end to end, as shown. Inthis configuration, the two condensing sections are at the forward andrear ends of the combination, and the two evaporator sections areabutted up against one another. The grill openings are shown at 64 inone unit and at 66 in the other unit, to conduct the flow of fresh airto the evaporator section when the fresh air flap is opened, and for theoutflow of returned air when the fresh air flap 42 is fully opened orpartially opened. An opening 67 can be provided to augment the flow offresh air to the evaporator.

In FIG. 15, a pair of modules 68 and 69 are placed in gangedrelationship in the manner as described hereinabove. A third module 71is placed at the other end of module 69, so that it is parallel to themodule 69, and not turned end for end as described hereinabove. Thus,the evaporator section of module 71 is adjacent the condenser section ofmodule 69, and in particular, the grill opening 72 are disposed adjacentto the condenser fan of module 69.

In FIG. 16, there are shown four modules 72, 73, 74 and 76, with modules72 and 73 being parallel with each other and with modules 74 and 76being parallel with respect to each other but being rotated end for endwith respect to the modules 72 and 73.

It should be recognized that the individual modules can be ganged in anycombination in order to meet the required capacity for the bus, whilealso being positioned so that the return air openings in the bus areregisterable with the respective inlet and outlet openings in theevaporator sections. While not shown, it should be understood that themodules can also be installed in positions so that they arelongitudinally spaced and not necessarily abutted up against each otheras shown.

In order to mount the modules, either as a single unit or incombinations as shown, it is desirable to have a method and apparatusfor easily attaching the modules to the rooftop of the bus. A preferredapproach is to have a pair of transversely spaced, longitudinallyextending rails 77 and 78 which are attached to a bus by appropriatefasteners or the like. The framework of the individual modules can then,in turn, be attached to the rails 77 and 79 by appropriate fastenerssuch as screws or the like. In FIG. 17, a pair of module frames 78 and81 are shown, with the frame 81 being turned end for end in a manner asdescribed hereinabove. This arrangement allows for the modules to beeasily attached to the rails such that they are all centered withrespect to the center line of the bus, and can be attached to the rails77 and 78 at any longitudinal position that is desired.

While this invention has been described with reference to a particularstructure disclosed herein, it should be understood that it is notconfined to the details set forth in this application, but is ratherintended to cover any modifications and changes as may come within thescope of the following claims.

We claim:
 1. An air conditioning module for a bus rooftop of the typehaving at least one return air opening for conducting the flow of returnair from the passenger compartment, and at least one supply air openingfor conducting the flow of conditioned air to the passenger compartment,comprising: a condenser section having at least one condenser coil and acondenser fan for causing ambient air to flow therethrough; and anevaporator section having at least one evaporator coil and at least oneevaporator fan for causing return air to flow from said return airopening through said evaporator section and to the at least one supplyair opening; wherein said evaporator section further comprises: a returnair compartment disposed in a lower portion of said evaporator sectionand adapted to receive a flow of return air from the return air opening;a vertical compartment disposed in an internal area and having on oneside a channel for the upward flow of return air from the return aircompartment and on another side a fan for drawing air downwardly andthen outwardly to an evaporator coil; a mixing compartment disposed inan upper area and fluidly communicating with both said channel and saidfan as well as the ambient air by way of a fresh air opening, such thatwithin said mixing compartment, fresh air is selectively mixed withreturn air and with the mixture passing into said fan.
 2. An airconditioning module as set forth in claim 1 wherein said at least onesupply air opening comprises two supply air openings, with one on eachside of the bus.
 3. An air conditioning module as set forth in claim 1wherein said condenser coil and condenser fan are so situated that thecondenser fan draws air through said condenser coil.
 4. An airconditioning module as set forth in claim 1 wherein said at least oneevaporator coil comprises two evaporator coils, with one on either sideof the bus.
 5. An air conditioning module as set forth in claim 4wherein said at least one evaporator fan comprises two evaporator fans,with each fan operating to blow air through its respective evaporatorcoil.
 6. An air conditioning module as set forth in claim 5 wherein saidevaporator fans are of the centrifugal type.
 7. An air conditioningmodule as set forth in claim 5 wherein said fans are orientated withtheir axises being vertical.
 8. An air conditioning module as set forthin claim 1 wherein there is included in association with said fresh airopening, a flap for selectively varying the size of the fresh airopening.
 9. An air conditioning module as set forth in claim 1 whereinthere is associated with said channel a flap for selectively varying thesize of an opening therein.
 10. An air conditioning module as set forthin claim 8 wherein said flap simultaneously varies the size of an upperopening in said channel.
 11. An air conditioning module as set forth inclaim 10 wherein said flap inversely varies the flow of air in saidfresh air opening and said channel.